A MEMS is known in which minute electrical parts and machine parts are integrated. The MEMS is exemplified by a micro-machine, a pressure sensor, and a micro-motor. The MEMS is manufactured by bonding semiconductor substrates such that a plurality of patterns are laminated. The semiconductor substrates require alignment in a horizontal direction when pressure welding in a vertical direction is performed.
An alignment unit is known which aligns the patterns at the time of bonding. The alignment apparatus is desired to have a smaller scale since the alignment unit is positioned in a vacuum atmosphere in which room temperature bonding is performed.
Japanese Patent 3,356,406 discloses a misalignment detecting apparatus which can detect positions of alignment marks without positioning an optical system between works to accurately detect misalignment of the works. The misalignment detecting apparatus detects the misalignment in an XY-plane between a plurality of works positioned in a z-axis direction with predetermined clearances, based on positions on the XY-plane of alignment marks formed on the opposing surfaces. A plurality of infrared imaging units are provided in accordance with the number of alignment marks to coaxially image the works from one direction through a common optical axis orthogonal to the XY-plane. The focused regions of the infrared imaging units are set in positions so that the alignment marks can be imaged, respectively.
Japanese Patent Publication (JP 2003-142534A) discloses an alignment method which makes it possible to align with high precision. In the alignment method, a recognition mark of a first bonding object having an alignment reference as an alignment recognition mark on the upper surface or in the inside, and a recognition mark of a second bonding object positioned below are aligned with high precision. In this alignment method, the first bonding object provided with the alignment recognition mark on the upper side or in the inside, and the second bonding object positioned below and provided with a recognition mark for the alignment with the first bonding object, are aligned by using a recognition section with two fields of vision put between the both objects. The conventional example is characterized in that the recognition mark on the upper side or in the inside of the first bonding object is recognized with an electromagnetic wave or a sound wave which can transmit through the first bonding object.
Japanese Patent Publication (JP-P2002-162206A) discloses an alignment method which makes it possible to adjust relative positions between bonding objects within permissible precision surely and easily, when alignment is performed for bonding the bonding objects and when one bonding object has covering material. In the alignment method, when a first bonding object and a second bonding object having the covering material are relatively aligned, a recognition section recognizes a position of an alignment mark of the first bonding object. A reference mark representing a position of the first bonding object is displayed on a screen at a position which corresponds to an outside region of the covering material of the second bonding object based on the recognition position, and the recognition section recognizes a position of an alignment mark of the second bonding object put on the outside of the covering material of the second bonding object. The recognition position is displayed on the screen, and a position of the second bonding object is corrected so that a position of the alignment mark of the second bonding object is within the predetermined permissible precision with respect to a position of the reference mark.
Japanese Patent Publication (JP P2003-218133A) discloses an alignment method in which it becomes possible to align bonding objects efficiently with high precision in a short time. In the alignment method, a first bonding object is aligned with a second bonding object. A first alignment is performed with respect to a rotation direction θ of the bonding object by recognizing at least two first recognition marks provided apart from at least one bonding object by a recognition section. A second alignment is performed with respect to parallel movement directions X and Y of the bonding object by recognizing a second recognition mark provided on at least one bonding object, by the recognition section.
Japanese Patent Publication (JP P2004-207436A) discloses a method in which makes it possible to perform pre-alignment of an orientation flat and wafer bonding with high precision without causing misalignment in a series of processes. In the wafer pre-alignment method, both edges facing each other of a chucked wafer are chucked with a wafer guide on a rotary table having a chuck mechanism and a rotation mechanism. A position of an orientation flat surface of the wafer is measured with an angle detecting section, and a wafer rotation angle is calculated. The orientation flat surface of the wafer is rotated to a predetermined angle calculated by the angle detecting section through rotation of the rotary table. Rotation to a pre-alignment position and alignment are performed after rotation to a reference position and alignment.